Field of the Invention
The invention relates to an image processing apparatus, an image processing method, and a non-transitory computer readable storage medium.
Description of the Related Art
In recent years, regarding moving images that are handled in digital televisions, digital cameras and the like, the number of pixels is increasing and the frame rate is increasing. Therefore, the data amounts of pixel data processed by these apparatuses are rapidly increasing. In these apparatuses, a memory such as a DRAM is used to process image data. In view of this, it is conceivable that the image data is compressed before being written into the memory. For example, at a compression rate of approximately 50%, it is possible to reduce the data amount without causing the deterioration of the visual image quality.
In the case of compressing an image, it is desirable that delay in the processing is small, and the apparatus is constituted by as simple a circuit as possible. Accordingly, as an encoding method for image compression suitable for such conditions, a DPCM (differential pulse code modulation) encoding method has been suggested (see Japanese Patent Laid-Open No. 2010-004514).
The DPCM encoding method is a method for performing compression by encoding the difference between reference data and data to be encoded by taking advantage of high spatial correlation between images, and can be realized by a relatively simple circuit.
If the encoding is performed without considering high spatial correlation specific to image data in a two dimensional array when performing compression by DPCM, it is highly possible that the encoding efficiency is decreased.